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Aging leads to a loss of cardiac non‐linear dynamics during sleep stages as assessed by statistical irreversibility
Author(s) -
Casali Karina Rabello,
Viola Antoine U,
Chellappa Sarah Laxhmi,
Tobaldini Eleonora,
Casali Adenauer Girardi,
Porta Alberto,
Montano Nicola
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1020.16
Subject(s) - heart rate variability , wakefulness , sleep (system call) , audiology , pathological , cardiology , polysomnography , skewness , detrended fluctuation analysis , psychology , medicine , heart rate , electroencephalography , neuroscience , mathematics , statistics , geometry , scaling , computer science , blood pressure , operating system
In physiological conditions heart rate variability (HRV) is mainly mediated through the modulation of sympathetic and vagal neural activities, balancing their relationship around an equilibrium state. Statistical irreversibility (SI) is a fundamental characteristic to evaluate disequilibrium in a dynamical system. Recently, SI studies applied to HRV in physiological and pathological conditions characterized by sympathetic predominance reported significant changes in SI. To test whether SI changes are also present in aging and modified through the sleep‐wake cycle, we applied the multidimensional time irreversibility test (surrogate data approach based on the skewness of the prime variations series) to HR time series obtained by polysomnographic ECG recordings in 12 young (21.1±0.8y) and 12 older (64.9±1.9y) healthy volunteers. In the young group, we found variations across sleep stages with predominance of SI at lower dimensions during wakefulness and at higher dimensions during sleep stages 3 and 4. In older subjects SI changes across sleep were completely lost, the total percentage (low and high dimensions) of SI was attenuated. These results indicate that linear and non linear dynamics in modulating HRV during sleep in young subjects have a distinctive pattern, that is lost with aging. This behaviour could be related to an increased risk for cardiovascular events in older people.